Developed by the Defence Signals Directorate (DSD), the mandate requires every federal government department to implement protective markings for inter-agency e-mail correspondence by March 2007.

But take-up has stalled with only a handful of agencies introducing the new standard in the past six months.

Known as ACS133, the standard was issued by the Attorney General's department under the Protective Security Manual (PSM).

It requires all federal government departments and agencies to implement e-mail filtering at the mail gateway to ensure no correspondence marked confidential or highly sensitive is read by government employees without an appropriate security clearance.

To date only the Australian Taxation Office (ATO), the Australian Transaction Reports and Analysis Center (Austrac), the Department of Immigration and Multicultural and Indigenous Affairs and AusAID have complied.